package cc.wsyw126.java.utils;

import java.io.*;
import java.util.Random;
import java.util.zip.*;

/**
 * Java实现数据压缩
 * ZLib压缩工具
 * Created by junpeng.yang on 17/1/10.
 */
public class ZLibUtils {

    /**
     * 压缩
     *
     * @param data 待压缩数据
     * @return byte[] 压缩后的数据
     */
    public static byte[] compress(byte[] data) {
        byte[] output = new byte[0];

        Deflater compresser = new Deflater();

        compresser.reset();
        compresser.setInput(data);
        compresser.finish();
        ByteArrayOutputStream bos = new ByteArrayOutputStream(data.length);
        try {
            byte[] buf = new byte[1024];
            while (!compresser.finished()) {
                int i = compresser.deflate(buf);
                bos.write(buf, 0, i);
            }
            output = bos.toByteArray();
        } catch (Exception e) {
            output = data;
            e.printStackTrace();
        } finally {
            try {
                bos.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        compresser.end();
        return output;
    }

    /**
     * 压缩
     *
     * @param data 待压缩数据
     * @param os   输出流
     */
    public static void compress(byte[] data, OutputStream os) {
        DeflaterOutputStream dos = new DeflaterOutputStream(os);

        try {
            dos.write(data, 0, data.length);
            dos.finish();
            dos.flush();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 解压缩
     *
     * @param data 待压缩的数据
     * @return byte[] 解压缩后的数据
     */
    public static byte[] decompress(byte[] data) {
        byte[] output = new byte[0];

        Inflater decompresser = new Inflater();
        decompresser.reset();
        decompresser.setInput(data);

        ByteArrayOutputStream o = new ByteArrayOutputStream(data.length);
        try {
            byte[] buf = new byte[1024];
            while (!decompresser.finished()) {
                int i = decompresser.inflate(buf);
                o.write(buf, 0, i);
            }
            output = o.toByteArray();
        } catch (Exception e) {
            output = data;
            e.printStackTrace();
        } finally {
            try {
                o.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        decompresser.end();
        return output;
    }

    /**
     * 解压缩
     *
     * @param is 输入流
     * @return byte[] 解压缩后的数据
     */
    public static byte[] decompress(InputStream is) {
        InflaterInputStream iis = new InflaterInputStream(is);
        ByteArrayOutputStream o = new ByteArrayOutputStream(1024);
        try {
            int i = 1024;
            byte[] buf = new byte[i];

            while ((i = iis.read(buf, 0, i)) > 0) {
                o.write(buf, 0, i);
            }

        } catch (IOException e) {
            e.printStackTrace();
        }
        return o.toByteArray();
    }

    public static void main(String[] args) throws Exception {

        Random random = new Random();

        StringBuilder sb = new StringBuilder("门店或权利违反蜂巢的业务属性规则\n" +
                "蜂巢ID10647\n" +
                "门店或权利ID,门店类型");

        for (int i = 0; i < 10; i++) {
            int num = random.nextInt(1227249);
            int num2 = random.nextInt(1227249);
            sb.append("\n" + num + "," + num2);
        }

        String inputStr = sb.toString();


//        System.out.println("字节压缩／解压缩测试");
//        System.out.println("输入字符串:" + inputStr);
        byte[] input = inputStr.getBytes();
        System.out.println("输入字节长度:" + input.length);

        byte[] data = ZLibUtils.compress(input);
        System.out.println("压缩后字节长度:" + data.length);

        byte[] output = ZLibUtils.decompress(data);
        System.out.println("解压缩后字节长度:" + output.length);
//        String outputStr = new String(output);
//        System.out.println("输出字符串:" + outputStr);

        File file = new File("x.gz");
        if (!file.exists())
            file.createNewFile();
        FileOutputStream fos = new FileOutputStream(file);
        byte[] bytes = data;
        fos.write(bytes);
    }
}
